Support additional compression levels for GzipCodec. Contributed by Ravi Mutyala.

(cherry picked from commit 18f9b77a321b225677ce23c503b41d21478fc4a7)
(cherry picked from commit e38c2ef6c54521a74cc2b787d78211f629aa07d8)
(cherry picked from commit 78a4c348940cd98548650c0a5adb981895cef201)

hadoop-common-project/hadoop-common/CHANGES.txt

@@ -1031,6 +1031,9 @@ Release 2.7.3 - UNRELEASED
     HADOOP-12413. AccessControlList should avoid calling getGroupNames in
     isUserInList with empty groups. (Zhihai Xu via cnauroth)
 
+    HADOOP-12794. Support additional compression levels for GzipCodec.
+    (Ravi Mutyala via junping_du)
+
   OPTIMIZATIONS
 
     HADOOP-12810. FileSystem#listLocatedStatus causes unnecessary RPC calls

hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/io/compress/zlib/ZlibCompressor.java

@@ -67,7 +67,47 @@ public class ZlibCompressor implements Compressor {
      * Compression level for fastest compression.
      */
     BEST_SPEED (1),
-    
+
+    /**
+     * Compression level 2.
+     */
+    TWO (2),
+
+
+    /**
+     * Compression level 3.
+     */
+    THREE (3),
+
+
+    /**
+     * Compression level 4.
+     */
+    FOUR (4),
+
+
+    /**
+     * Compression level 5.
+     */
+    FIVE (5),
+
+
+    /**
+     * Compression level 6.
+     */
+    SIX (6),
+
+    /**
+     * Compression level 7.
+     */
+    SEVEN (7),
+
+    /**
+     * Compression level 8.
+     */
+    EIGHT (8),
+
+
     /**
      * Compression level for best compression.
      */

hadoop-common-project/hadoop-common/src/test/java/org/apache/hadoop/io/compress/zlib/TestZlibCompressorDecompressor.java

@@ -122,6 +122,31 @@ public class TestZlibCompressorDecompressor {
     }
   }
 
+  @Test
+  public void testZlibCompressorDecompressorWithCompressionLevels() {
+    Configuration conf = new Configuration();
+    conf.set("zlib.compress.level","FOUR");
+    if (ZlibFactory.isNativeZlibLoaded(conf)) {
+      byte[] rawData;
+      int tryNumber = 5;
+      int BYTE_SIZE = 10 * 1024;
+      Compressor zlibCompressor = ZlibFactory.getZlibCompressor(conf);
+      Decompressor zlibDecompressor = ZlibFactory.getZlibDecompressor(conf);
+      rawData = generate(BYTE_SIZE);
+      try {
+        for (int i = 0; i < tryNumber; i++)
+          compressDecompressZlib(rawData, (ZlibCompressor) zlibCompressor,
+                  (ZlibDecompressor) zlibDecompressor);
+        zlibCompressor.reinit(conf);
+      } catch (Exception ex) {
+        fail("testZlibCompressorDecompressorWithConfiguration ex error " + ex);
+      }
+    } else {
+      assertTrue("ZlibFactory is using native libs against request",
+              ZlibFactory.isNativeZlibLoaded(conf));
+    }
+  }
+
   @Test
   public void testZlibCompressDecompress() {
     byte[] rawData = null;